1. Field of the Invention
The present invention relates to a method for forming a superconducting circuit for use for an electron element, a coil, a circuit substrate, etc.
2. Description of the Related Art
In place of a metal superconductor which produces a superconducting phenomenon at a very low temperature called a liquid helium temperature, a ceramics superconductor has been newly highlighted and actively developed in recent times, such as a ceramics superconductor producing a superconducting phenomenon at a temperature exceeding a liquid nitrogen temperature, that is, a ceramics superconductor whose critical temperature Tc is above the liquid nitrogen temperature. Recent attention has been focused particularly on a Y-Ba-Cu-O based one, such as YBa.sub.2 Cu.sub.3 O.sub.7 -.delta. (.delta.=0 to 0.5) (Tc=90 to 95 K), including one obtained by replacing Y with rare earth elements; a Bi-Sr-Ca-Cu-O based one, such as Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8 and Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 (Tc=80 to 110 K); and a T.lambda.-Ba-Ca-Cu-O based one, such as T.lambda..sub.2 Ba.sub.2 CaCu.sub.2 O.sub.6, T.lambda..sub.2 Ba.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 and T.lambda.Ba.sub.2 Ca.sub.2 Cu.sub.3 O .sub.8.5 (Tc=90 to 125 K), and one obtained by partially replacing Bi, T.lambda. of the aforementioned two superconductors with Pb, Sb, In.
Since the ceramics superconductor displays an excellent electrical property at the critical temperature exceeding the liquid nitrogen temperature, it is with used in for example, an electronic element, an electric cable, a magnetic coil, a circuit conductor and a magnetic shield.
A method for forming a superconducting circuit is by forming a pattern, like an ordinary circuit board conductor formation method, with the use of a photosensitive resist resin and performing an etching step (a dry or a wet etching step) with the pattern used as an etching mask.
This method, however, has the drawbacks in that a circuit section is damaged by an overetch and/or sideetch at the etching step to cause a bad effect on the property of a conductor and that a dimensional error is produced for a circuit section obtained. Furthermore, as a noncircuit section is formed through removal by the etching step, an unevenness (a step) is formed over the circuit and noncircuit sections, adversely affecting a degree of flatness over the substrate and hence preventing a problem in the provision of, for example, elements in and on the substrate surface. It is, therefore, necessary to provide an insulation layer relative to the noncircuit section and to lessen uneven surfaces of the circuit and noncircuit sections.